CFDs are a leverage product and can involve a significant risk of loss. Trading CFDs may not be suitable for all, therefore you should ensure that you understand the risks involved and take into account your individual circumstances.
Trader's Glossary

What is Reserve Currency?

A reserve currency is a currency that is held by central and commercial banks in order to service debts, purchase commodities (which are ordinarily priced in the reserve currency), and to influence exchange rates. This currency is held in reserve so as to minimise exchange rate risk. Since the end of the Second World War the US dollar has been the world’s reserve currency.